The research objectives of this project are: (1) to compare the performances of patients with cerebral disease with those of normal subjects and patients in other diagnostic categories on perceptual, cognitive, psychomotor and language tasks with the aim of defining the distinctive performance characteristics of patients with cerebral disease; (2) to make within-group comparisons of patients with cerebral disease with the aim of determining the relationship between various performance characteristics and locus of lesion; (3) to identify the more basic disabilities underlying the defective performances of patients with cerebral disease on perceptual, cognitive, psychomotor and language tasks; (4) to develop standardized objectve procedures for clinical and investigative use; (5) to undertake historical analyses designed to clarify certain persisting conceptual and methodological problems in clinical neuropsychology.